Plasma processing system and method

ABSTRACT

A plasma processing system and method for operating a diagnostic system in conjunction with a plasma processing system are provided. The diagnostic system is in communication with a plasma processing chamber of the plasma processing system and includes a diagnostic sensor to detect a plasma process condition. The diagnostic system is configured to substantially reduce contamination of the diagnostic sensor. The method includes substantially reducing contamination of the diagnostic sensor and detecting a condition of the plasma process and/or a substrate in the processing chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of International Application No. PCT/US03/30051,filed Sep. 25, 2003, which relies for priority upon U.S. ProvisionalApplication No. 60/414,349, filed on Sep. 30, 2002, the entire contentsof both of which are incorporated herein by reference in theirentireties.

This continuation of PCT application is also related to InternationalApplication No. PCT/US03/26208, filed Aug. 21, 2003, which relies topriority on U.S. Provisional Patent Application No. 60/414,348, filedSep. 30, 2003, the entire contents of both of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to plasma processing and more particularlyto reducing contamination of a diagnostic system used in plasmaprocessing.

2. Description of Background Information

Typically, plasma is a collection of species, some of which are gaseousand some of which are charged. Plasmas are useful in certain processingsystems for a wide variety of applications. For example, plasmaprocessing systems are of considerable use in material processing and inthe manufacture and processing of semiconductors, integrated circuits,displays and other electronic devices, both for etching and layerdeposition on substrates, such as, for example, semiconductor wafers.

Diagnostic methods are widely used to monitor plasma processes andassociated substrates and to determine an end point of a plasma process,for example, a plasma etching process. Diagnostic methods can includeoptical diagnostic methods or pressure measurement methods, for example.Maintenance is required when the diagnostic sensor becomes contaminatedwith plasma by-products.

SUMMARY OF THE INVENTION

One aspect of the invention is to provide a plasma processing system incommunication with a diagnostic system. The plasma processing systemcomprises a chamber containing a plasma processing region, a chuckconstructed and arranged to support a substrate within the chamber inthe processing region and a chamber opening formed in a wall of thechamber to enable plasma within the plasma processing region to exit thechamber. A plasma generator is positioned in communication with thechamber and is constructed and arranged to generate a plasma during aplasma process in the plasma processing region. The diagnostic systemincludes a passageway formed between the plasma processing region and adiagnostic sensor. The passageway has a predetermined length and apredetermined diameter. The passageway is configured to have a length todiameter ratio, which is provided by dividing the predetermined lengthof the passageway by the predetermined diameter of the passageway, of atleast 4.

Another aspect of the invention is to provide a method for operating adiagnostic system in communication with a plasma processing system. Theplasma processing system has a chamber containing a plasma processingregion in which a plasma can be generated during a plasma process andthe diagnostic system. The diagnostic system monitors the plasmaprocessing region and/or a substrate in the chamber. The methodcomprises providing a passageway formed between the plasma processingchamber and the diagnostic sensor with the passageway having a length todiameter ratio of at least 4. The method further comprises detecting anemission from the plasma processing region and/or substrate through anopening in the chamber and reducing contamination of the diagnosticsystem. Thus, a method can be provided to reduce contamination of adiagnostic system, e.g., an optical diagnostic assembly or a diagnosticassembly.

In embodiments of the invention, the diagnostic system includes acontamination reducing structure which is configured to reducecontamination of the passageway associated with the diagnostic sensor.In one embodiment, the contamination reducing structure can include agas purge passageway configured to introduce a purge gas into thepassageway. In other embodiments, the contamination reducing structurecan include an electric field generator, a magnetic field generator, atemperature controlled system, or a combination of at least two of anelectric field generator, a magnetic field generator, a temperaturecontrolled system and a gas purge passageway to reduce contamination ofthe passageway associated with the diagnostic sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, of embodiments of the invention, togetherwith the general description given above and the detailed description ofthe embodiments given below, serve to explain the principles of theinvention wherein:

FIG. 1 is a diagrammatic cross section of an embodiment of a plasmaprocessing system in accordance with the principles of the invention,showing a plasma processing chamber in communication with a diagnosticsystem;

FIG. 2 is a diagrammatic cross section of a diagnostic system, whichshows a pre-chamber area formed in the diagnostic system;

FIG. 3 is a diagrammatic cross section of a diagnostic system, whichshows a temperature controlled system associated with the pre-chamberarea;

FIG. 4 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows an electric field generator associatedwith the pre-chamber area;

FIG. 5 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows a magnetic field generator of thediagnostic system;

FIG. 6 is a diagrammatic cross section taken through the line 6-6 ofFIG. 5, which shows a polarization direction and magnetic field lines ofthe magnetic field generator shown in FIG. 5;

FIG. 7 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows an alternative magnetic field generatorof the diagnostic system;

FIG. 8 is a diagrammatic cross section taken through the line 8-8 ofFIG. 7, which shows a polarization direction and magnetic field lines ofthe magnetic field generator shown in FIG. 7;

FIG. 9 is a diagrammatic cross section of another embodiment of thediagnostic system, which includes a passageway having a predeterminedlength and a predetermined diameter so to eliminate the pre-chamber areashown in FIG. 2;

FIG. 10 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows a gas purge passageway operativelyassociated with the diagnostic system shown in FIG. 9;

FIG. 11 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows a restrictor element restricting thepassageway to have a predetermined length and a predetermined diameter;

FIG. 12 is a diagrammatic cross section of another embodiment of therestrictor element;

FIG. 13 is a diagrammatic cross section of another embodiment of therestrictor element, which shows a tapered configuration of therestrictor element which allows the restrictor outer diameter toincrease or decrease along the passageway;

FIG. 14 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows a gas purge passageway operativelyassociated with the diagnostic system shown in FIG. 11;

FIG. 15 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows a gas purge passageway operativelyassociated with the diagnostic system shown in FIG. 12;

FIG. 16 is a diagrammatic cross section of another embodiment of thediagnostic system, which shows a gas purge passageway operativelyassociated with the diagnostic system shown in FIG. 13; and

FIG. 17 is a flow chart showing a method of operating a diagnosticsystem in communication with a plasma processing system in accordancewith principles of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows an embodiment of a plasma processing system according toprinciples of the invention. The plasma processing system, generallyindicated at 10, is in communication with a diagnostic system, generallyindicated at 12. The diagnostic system 12 can be any diagnostic system,such as an optical diagnostic assembly, an imaging device viewport, apressure sensor, a mass spectrometer, an ion flux and energy measurementsystem, or a plasma RF harmonic measurement system, for example.

The plasma processing system 10 comprises a plasma process chamber,generally indicated at 14, that defines a plasma processing region 16 inwhich a plasma 18 can be generated. A chuck or electrode 30 can bepositioned in the chamber 14 and is constructed and arranged to supporta substrate 20, which can be a semiconductor wafer, for example, withinthe chamber 14 in the processing region 16. The substrate 20 can be asemiconductor wafer, integrated circuit, a sheet of a polymer materialto be coated, a metal to be surface hardened by ion implantation, orsome other semiconductor material to be etched or deposited, forexample.

Although not shown, coolant can be supplied to the chuck 30, forexample, through cooling supply passages coupled to the chamber 14. Eachcooling supply passage can be coupled to a cooling supply source. Forexample, the cooling supply passages can be individually connected tothe cooling supply source. Alternatively, cooling supply passages can beinterconnected by a network of interconnecting passages, which connectall cooling supply passages in some pattern.

Generally, plasma generation gas, which can be any gas that is ionizableto produce a plasma, is introduced into the chamber 14 to be made into aplasma, for example, through a gas inlet 26. The plasma generation gascan be selected according to the desired application as understood byone skilled in the art and can be nitrogen, xenon, argon, carbontetrafluoride (CF₄) or octafluorocyclobutane (C₄F₈) for fluorocarbonchemistries, chlorine (Cl₂), hydrogen bromide (HBr), or oxygen (O₂), forexample.

The gas inlet 26 is coupled to the chamber 14 and is configured tointroduce plasma processing gases into the plasma processing region 16.A plasma generator in the form of upper electrode 28 and lower electrode30 can be coupled to the chamber 14 to generate the plasma 18 within theplasma processing region 16 by ionizing the plasma processing gases. Theplasma processing gases can be ionized by supplying RF and/or DC powerthereto, for example. In some applications, the plasma generator can bean antenna or RF coil capable of supplying RF power, for example.

A variety of gas inlets or injectors and various gas injectingoperations can be used to introduce plasma processing gases into theplasma processing chamber 14, which can be hermetically sealed and canbe formed from aluminum or another suitable material. The plasmaprocessing gases are often introduced from gas injectors or inletslocated adjacent to or opposite from the substrate. For example, asshown in FIG. 1, gases supplied through the gas inlet 26 can be injectedthrough an inject electrode (upper electrode 28) opposite the substratein a capacitively coupled plasma (CCP) source. The power supplied to theplasma can ignite a discharge with the plasma generation gas introducedinto the chamber 14, thus generating a plasma, such as plasma 18.

Alternatively, in embodiments not shown, the gases can be injectedthrough a dielectric window opposite the substrate in a transformercoupled plasma (TCP) source. Other gas injector arrangements are knownto those skilled in the art and can be employed in conjunction with theplasma processing chamber 14.

The plasma processing chamber 14 is fitted with an outlet having a firstvacuum pump 32 and a valve 34, such as a throttle control valve, toprovide gas pressure control in the plasma process chamber 14.

Various leads (not shown), for example, voltage probes or other sensors,can be coupled to the plasma processing system 10.

An opening 22 extends radially from the process chamber 14 through achamber wall 36 to the diagnostic system 12. Generally, in diagnosticassemblies having pressure sensors or mass spectrometers, the opening 22can be made large to allow faster sensor response. In optical diagnosticassemblies, the opening 22 can be made large to allow a stronger signalor signals to be transmitted to and collected by the optical diagnosticassembly or detector.

The diagnostic system 12 is generally vacuum tight and can be formed incommunication with the process chamber 14 to enable communication withthe plasma processing region 16, as will be described in further detailbelow.

A gate valve (not shown) can be coupled to the plasma process chamber14, adjacent to the chamber opening 22 and between the plasma processchamber 14 and the diagnostic system 12. The gate valve can be providedto allow isolation of the diagnostic system 12 from the plasmaprocessing chamber 14 for maintenance operations, such as calibrating orrecalibrating sensors in a diagnostic assembly, cleaning a window in anoptical diagnostic assembly, replacing the window in an opticaldiagnostic assembly or periods of gas purge, for example. The gate valveis not essential to the invention and is omitted from the embodimentshown in FIG. 1. The gate valve can be provided or eliminated from thesystem 10 depending on the plasma process being performed by the system10.

As shown in FIG. 2, one embodiment of the diagnostic system 12 includesa mounting portion 38 and a diagnostic sensor 40. The mounting portion38 of the diagnostic system 12 can be coupled to the chamber wall 36 ofthe plasma process chamber 14 by a mounting flange 42 (or a plurality ofthe same). Fasteners (not shown), such as nuts and bolts, or screws, forexample, can extend through the mounting flange 42 to couple themounting flange 42 to the chamber wall 36. One or more mounting walls44, which can have a tubular or cylindrical configuration, can extendfrom the mounting flange 42. End portions 48 can extend outwardly fromthe mounting walls 44 to couple the diagnostic sensor 40 thereto, asshown in FIG. 2. Alternatively, the mounting flange 42 and the mountingwalls 44 can be formed in other configurations as well.

As shown in FIGS. 1 and 2, the mounting walls 44 can define a passageway46 having a selected diameter therein in a longitudinal directionthereof. The passageway 46 is configured to allow communication betweenthe plasma processing chamber 14 and the diagnostic sensor 40 of thediagnostic system 12 (as indicated by an arrow labeled A in FIG. 1). Thediameter of the passageway 46 can be substantially the same as, smallerthan or larger than the diameter of the opening 22 to allow transmissionto the diagnostic sensor 40.

A flow restrictor element 50 can be mounted within the mounting walls 44of the diagnostic system 12, by adhesive, bonding material or othersuitable fasteners, to determine the amount of light or gas that reachesthe diagnostic sensor 40 (e.g., by restricting the flow through theopening 22 formed in the chamber wall 36). The restrictor element 50extends between the diagnostic sensor 40 and the plasma processingregion 16. The diameter of the passageway 46 is effectively determinedby the size of the restrictor element 50. The restrictor element 50 canbe integrally formed with the mounting portion 38. That is, rather thanhaving a separate restrictor element, the inner wall of mounting portion38 inherently defines a restrictor.

The flow restrictor element 50, the mounting portion 38 or both the flowrestrictor element 50 and the mounting portion 38 can be made frommetals, e.g., aluminum, anodized aluminum and stainless steel,dielectric materials, e.g., ceramics such as quartz, alumina,silicon-carbide and silicon-nitride, semiconductor materials, e.g.,silicon, doped silicon and other materials. For example, in plasmaprocesses involving aggressive chemistries, such as fluorine-basedchemistries, a flow restrictor element made from semiconductormaterials, e.g., silicon, can reduce the concentration of aggressivespecies.

The mounting walls 44 can also optionally include a gas purge passageway54 coupled thereto for communication with a pre-chamber area 52, formedbetween the restrictor element 50 and the diagnostic sensor 40. The gaspurge passageway 54 can be integrally formed with the mounting walls 44,as shown in FIG. 2, or alternatively, can be coupled thereto withfasteners (not shown), such as nuts and bolts, or screws, for example.

The gas purge passageway 54 allows a purge gas to be provided to thepre-chamber area 52, for example (as indicated by an arrow labeled B inFIG. 2). When purge gas is provided to the pre-chamber area 52, apressure within the pre-chamber area 52 is increased relative to apressure in the plasma processing region 16, thus creating a pressuredifference between the pre-chamber area 52 and the plasma processingregion 16. The pressure difference establishes a flow from thepre-chamber area 52 to the plasma processing chamber 14 (as indicated byan arrow labeled C in FIG. 2), which reduces upstream diffusion ofcontaminants, e.g., plasma-borne chemical species, from the plasma 18 tothe diagnostic sensor 40. The diameter size of the passageway 46 incombination with the pressure difference and established flow betweenthe pre-chamber area 52 and the plasma processing region 16, alsoreduces plasma light-up in the pre-chamber area 52. For example, therestrictor element 50 can be sized to provide the passageway 46, whichcan have a diameter selected from the range of 0.1 cm to 2.5 cm, forexample. The diameter of the passageway 46 can be smaller than thediameter of the opening 22 to help reduce contaminant backflow andplasma light-up.

In plasma processes that do not involve aggressive chemistry, the gaspurge passageway 56 and the flow restrictor element 50 may be eliminatedfrom the diagnostic system 12. This is because contamination of thediagnostic system 12, e.g., the passageway 46 or the diagnostic sensor40, is greater in processes that involve aggressive chemistry, and withnon-aggressive chemistry there is no need to restrict the flow or usepurge gas.

A spectrometer (not shown) can be incorporated in the diagnostic sensor40 to detect a plasma process condition based on an optical emission,e.g., light, from the plasma 18, or may be separate from the sensor 40.The spectrometer or the detector system can be associated with aphotomultiplier tube, a CCD or other solid state detector to at leastpartially detect the plasma process condition, such as an endpoint of aplasma process, for example. However, other optical devices capable ofanalyzing an optical emission or properties of a wafer, e.g., filmsassociated with the wafer, can be used as well.

A controller 56 capable of generating control voltages sufficient tocommunicate and activate inputs to plasma processing system 10 as wellas capable of monitoring outputs from the plasma processing system 10can be coupled to the plasma processing system 14. For example, thecontroller 56 can be coupled to and can exchange information with theupper electrode 28, the lower electrode 30 and the gas inlet 26. Aprogram, which can be stored in a memory, can be utilized to control theaforementioned components of plasma processing system 10 according to astored process recipe. Furthermore, controller 56 is capable ofcontrolling the components of the diagnostic system 12. For example, thecontroller 56 can be configured to control the diagnostic sensor 40.Alternatively, multiple controllers 56 can be provided, each of whichbeing configured to control different components of either the plasmaprocessing system 10 or the diagnostic system 12, for example. Oneexample of the controller 56 is an embeddable PC computer type PC/104from Micro/SYS of Glendale, Calif.

FIG. 3 shows a diagnostic system 112, which is an alternative embodimentof the diagnostic system 12. Elements in the diagnostic system 112 thatare similar to elements of the diagnostic system 12 have correspondingreference numerals. The passageway 46, the restrictor element 50, thepre-chamber area 52 and the gas purge passageway 54 can be employed in asubstantially identical manner as set forth above with respect todiagnostic system 12. However, the gas purge passageway 54 can beomitted depending on the plasma process application.

The diagnostic system 112 includes a mounting portion 138, which can bemade from the same materials as the mounting portion 38 described above.The mounting portion 138 has a mounting flange 142 (or a plurality ofthe same) with fasteners (not shown) to couple the mounting flange 142to the chamber wall 36. A plurality of mounting walls 144 a, 144 b,which can have a tubular or cylindrical configuration, can extend fromthe mounting flange 142. The mounting walls 144 a, 144 b form a fluidchamber 143 therebetween. The fluid chamber 143 can have a tubular orcylindrical configuration and can be in communication with a fluid inlet158, which is coupled to the outer mounting wall 144 b. The fluid inlet158 is configured to carry fluid, e.g., gas or liquid, to the fluidchamber 143. A fluid outlet 160 is coupled to the mounting wall 144 b incommunication with an opposite end of the fluid chamber 143 from thefluid inlet 158. The fluid inlet 158 or the fluid outlet 160 can beintegral with the wall portion 144 b or can be fastened to the wallportion 144 b on opposite sides of the passageway 46 with suitablefasteners. The fluid inlet 158 and the fluid outlet 160 can bepositioned anywhere along the mounting wall 144 b. For example, thefluid inlet 158 can be provided adjacent the gas purge passageway 54 andthe fluid outlet 160 can be provided on the opposite side of thepassageway 46 or vice versa.

Depending on the plasma process application, a temperature of the fluidintroduced into the fluid chamber 143 can be selected, e.g., an elevatedtemperature (e.g., 250° C.) or a reduced temperature (e.g., −196° C.),with respect to a gas temperature inside of the pre-chamber area 52 andthe passageway 46. An elevated temperature can generally reduce filmcontamination in some plasma chemistries, while a reduced temperature,e.g., cryogenic, can cause rapid adsorption of contaminants in theplasma in the passageway 46 so that contaminants do not reach thediagnostic sensor 40. Thus, the fluid temperature can be controlled andselected to help reduce contamination of the diagnostic sensor 40.

To provide elevated temperatures, the wall portion 144 b and the chamber143 can be replaced with a heater, e.g., an electric heater, wrappedaround an outer periphery of the wall portion 144 a. Alternatively, theheater could be implemented in combination with the wall portion 144 band the fluid chamber 143.

FIG. 4 shows a diagnostic system 212, which is an alternative embodimentof the diagnostic systems 12, 112. Elements in the diagnostic system 212that are similar to elements of the diagnostic systems 12, 112 havecorresponding reference numerals. The passageway 46, the restrictorelement 50, the pre-chamber area 52 and the gas purge passageway 54 canemployed in a substantially identical manner as set forth above withrespect to diagnostic systems 12, 112. However, the gas purge passageway54 can be omitted depending on the plasma process application.

The diagnostic system 212 includes a mounting portion 238, which can bemade from the same materials as the mounting portion 38 described above.The mounting portion 238 has a mounting flange 242 (or a plurality ofthe same) with fasteners (not shown) to couple the mounting flange 242to the chamber wall 36. A mounting wall 244, which can have a tubular orcylindrical configuration, can extend from the mounting flange 242. Themounting wall 244 is configured to receive an insulator 262, such assilica (quartz), alumina or another dielectric material, and an electricfield generator 264 mounted thereto, e.g., by fasteners, adhesive,bonding material or other suitable fasteners. The insulator 262insulates an outer portion of the electric field generator 264.

The mounting wall 244 can have an opening 266 formed therein forreceiving a feedthrough element 268. The feedthrough element 268 couplesthe electric field generator 264, which can include an annular electrodeor a plurality of electrodes, with a power supply 270. The power supply270 can supply either DC or radio frequency (RF) bias power to theelectric field generator 264.

Depending on the plasma process application, either DC or RF biasedpower can be used to repel plasma from the passageway 46. For example, astrong negative DC bias at moderate to high pressures, e.g., pressuresequal to or greater than about 40 mTorr, can substantially reduce plasmain the processing chamber 14 from entering the pre-chamber 52 and thepassageway 46 or vicinities thereof by repelling electrons in the plasmafrom the passageway 46. Other electrodes can be used to provide the DCor RF power such that the electrode can be biased to the same charge ofthe plasma charged species to repel those species (e.g., a positiveelectrode can be used to repel ions in the plasma). In other words, a“standing-off” effect is provided, in which the plasma is confined to anarea outside the passageway 46 or a vicinity thereof. At the moderate tohigh pressures, ions in the plasma can frequently collide with otherparticles in the plasma to further reduce plasma light-up within thepassageway 46 or a vicinity thereof.

FIG. 5 shows a diagnostic system 312, which is an alternative embodimentof the diagnostic systems 12, 112, 212. Elements in the diagnosticsystem 312 that are similar to elements of the diagnostic systems 12,112, 212 have corresponding reference numerals. The passageway 46, therestrictor element 50, the pre-chamber area 52 and the gas purgepassageway 54 can employed in a substantially identical manner as setforth above with respect to diagnostic systems 12, 112. However, the gaspurge passageway 54 can be omitted depending on the plasma processapplication.

The diagnostic system 312 includes a mounting portion 338, which can bemade from the same materials as the mounting portion 38 described above.The mounting portion 338 has a mounting flange 342 (or a plurality ofthe same) with fasteners (not shown) to couple the mounting flange 342to the chamber wall 36. A mounting wall 344, which can have a tubular orcylindrical configuration, can extend from the mounting flange 342. Themounting wall 344 has an opening 372 formed therein, which is configuredto receive a magnetic field generator 376 and a magnetic field leakagereducing member 374 therein. The magnetic field generator 376, which caninclude one or more permanent magnets or current-carrying coils, isconfigured to produce a magnetic field (generally indicated at 378 inFIG. 6) across the passageway 46. The magnetic field generator 376 canbe mounted within the opening 372 of the mounting wall 344 along withthe magnetic field leakage reducing member 374 by fasteners, adhesive,bonding material or other suitable fasteners, for example.

The magnetic field leakage reducing member 374 can be an iron ring, forexample, or any other structure capable of reducing leakage of themagnetic field outside the passageway 46. Thus, the possibility of themagnetic field 378 affecting the plasma process within the plasmaprocessing chamber 14, and the diagnostic system 40, can be reduced.

Depending on the plasma process application, the magnetic fieldgenerator 376 can be configured to form the magnetic field 378 acrossthe passageway such that plasma is substantially prevented from enteringthe pre-chamber 52 and the passageway 46 or vicinities thereof. In otherwords, the magnetic field 378 can shield plasma generally outside(within the plasma processing chamber 14) the passageway 46.

FIG. 6 shows a cross-sectional view of the mounting wall 344, themagnetic field leakage reducing member 374 and the magnetic fieldgenerator 376 in which one example of the magnetic field 378 is shownacross the passageway 46. The restrictor element 50 is eliminated fromFIG. 6 for simplicity. As illustrated, the magnetic field generator 376includes a plurality of permanent magnets 380 positionedcircumferentially around the passageway 46 to form a dipole ring. Inthis example, the magnets 380 are positioned relative to one anothersuch that adjacent magnets 380 have polarization directions 382 (shownas bolded arrows) successively directed in a counter-clockwisedirection. Although not shown, the magnets 380 can be oriented to besymmetric with respect to a horizontal axis (shown as a dotted line inFIG. 6). FIG. 6 shows 16 magnets 380, each having a polarizationdirection 382 that is separated from the polarization direction 382 ofan adjacent magnet 380 by about 45°. However, other magneticconfigurations are possible, e.g., when more or less magnets 380 areimplemented, and the separation angle is changed accordingly, e.g., theangle between adjacent magnet polarization directions is twice theseparation angle between the magnets.

The configuration of magnets 380 shown in FIG. 6 produces the magneticfield 378, which has field lines 384 that extend across the passageway46. In the magnetic field 378, particles readily spiral along the fieldlines 384 and only slowly diffuse across the field lines 384 and intothe passageway 46, which helps to shield the passageway 46 or a vicinitythereof from plasma.

FIG. 7 shows a diagnostic system 412, which is an alternative embodimentof the diagnostic systems 312. The diagnostic system 412 issubstantially identical in construction and operation as the diagnosticsystem 312, but includes a magnetic field generator 476, which is analternative embodiment of the magnetic field generator 376. Although notshown in this embodiment, the magnetic field leakage reducing member 374could be positioned around the magnetic field generator 476, asdescribed above with respect to the magnetic field generator 376.

The diagnostic system 412 includes a mounting portion 438, which can bemade from the same materials as the mounting portion 38 described above.The mounting portion 438 has the mounting flange 342 (or a plurality ofthe same) and the mounting wall 344 described above. The magnetic fieldgenerator 476 can be mounted within the opening 372 by appropriatemounting elements.

FIG. 8 shows the magnetic field generator 476 including a plurality ofpermanent magnets 480 positioned circumferentially around the passageway46. Each magnet 480 has a polarization direction 482 directed radiallyinward toward the passageway 46 (as shown in FIG. 8) or directed outwardaway from the passageway 46. However, more or less magnets 480 can beprovided and other magnetic configurations are possible, e.g., thepolarization direction 482 of each magnet 480 can be alternated betweenadjacent magnets 480, e.g., one magnet can have a polarization directiondirected radially inward and adjacent magnets can have a polarizationdirection directed radially outward, or vice versa.

The configuration of magnets 480 shown in FIG. 8 produces the magneticfield 478, which has field lines 484, which extend into the passageway46. Depending on the plasma process application, the magnetic field 478can be formed such that plasma entering the pre-chamber 52 and thepassageway 46 or vicinities thereof is substantially reduced. In otherwords, the magnetic field 478 can at least partially shield plasma fromentering the pre-chamber 52 and the passageway 46 or vicinities thereof.

The magnetic field 478 is less strong than the magnetic field 378described above because the field strength at the center of thepassageway 46 is zero. However, with its lesser strength, the magneticfield 478 can be used in plasma processes in which strong magneticfields induce undesirable effects, which can affect measurement, e.g.,providing a pumping effect on the plasma that affects pressuremeasurements.

With respect to FIGS. 6 and 8, alternate configurations of the magneticfields 378, 478 are possible and can be formed by providing multiplerows of magnets 380, 480, respectively, with the same or alternatingpolarization directions 382, 482 to achieve other different fieldconfigurations, for example.

In the above embodiments, shown in FIGS. 2-5 and 7, the gas purgepassageway 56 is provided to supply a purge gas into the passageway 46and the pre-chamber area 52. As described above, the supply of purge gascan reduce backflow of chamber process gas into the passageway, whichreduces contamination of the diagnostic sensor 40. The gas purgepassageway 56 supplied purge gas into the passageway 46 and thepre-chamber area 52 so as to not disturb existing chamber gas flowsignificantly, e.g., the purge gas flow should not create a disturbinggas jet that extends far into the chamber 14.

FIGS. 9-16 show diagnostic systems that are alternative embodiments ofthe diagnostic system 12. The diagnostic systems shown in FIGS. 9-16each includes a flow restriction having a length to diameter ratio of atleast 4 to reduce backflow of chamber process gas into the passagewayand to reduce contamination of the diagnostic sensor. In each of thebelow described diagnostic systems, the chamber wall has a thicknessthat is less than the predetermined length of the passageway.

FIG. 9 shows a diagnostic system 512 that is an alternative embodimentof the diagnostic system 12, which operates in substantially the samemanner as the diagnostic system 12. The diagnostic system 512 includes amounting portion 538, which can be made from the same materials as themounting portion 38 described above. The mounting portion 538 has amounting wall 544 coupled to the chamber wall 36 by one or morefasteners 537. The fastener(s) may be one or more of a seal, an O-ringor any other type of sealing fastener capable of coupling the mountingwall 744 to the chamber wall 36.

A diagnostic sensor, which is not shown for simplicity, can beoperatively associated with the diagnostic system 512. The diagnosticsensor can operate in substantially the same manner as the sensor 40shown in FIG. 1 and can be operatively associated with a diagnosticsensor element 539. The diagnostic sensor element 539, which can be awindow or diagnostic aperture, for example, can be coupled to themounting wall 544. Because the diagnostic sensor element 539 is directlymounted onto the mounting wall 544, the diagnostic system 512 does notinclude a pre-chamber area.

The mounting wall 544 has an interior surface 545 that defines apassageway 546 having a predetermined diameter D. The diameter D of thepassageway 546 can be equal to, smaller or larger than the diameter ofthe opening 22 formed in the chamber wall 36.

The passageway 546 has a predetermined length L, which can be defined inthis embodiment as the distance from the chamber opening 22 to thediagnostic sensor element 539 or to the diagnostic sensor. The length Lcan be selected to be longer than the gas mean free path of molecules ofa contaminant at the selected process conditions, e.g., processingchamber pressure, chamber gas flow and chamber gas temperature. Becausethe length L of the passageway 546 is selected to be X times longer thanthe gas mean free path of contaminant molecules at the selected processconditions, a contaminant molecule will generally experience X number ofcollisions on its way through the passageway 546. Thus, the number ofcontaminant molecules that reach the diagnostic sensor or the diagnosticsensing element 539 is reduced, at least partially due to the X numberof collisions. In this conceptual example, X may represent a numbergreater than zero, e.g., 25, 55, 85 or higher. However, X can beselected to be any number depending on the gas mean free path ofcontaminant molecules and the selected process conditions, which canvary depending on the plasma process.

The length L and the diameter D of the passageway 546 can be selected toprovide a length to diameter ratio (L/D) of at least 4, which can beobtained by dividing the length L of the passageway by the diameter D ofthe passageway 546. The passageway 546 can be configured to providelength to diameter ratios greater than 4 depending on the plasma processbeing used or process characteristics, e.g., processing chamberpressure, chemistry, gas flow, and temperature, thereof.

FIG. 10 shows a diagnostic system 612, which has substantially the sameconstruction as the diagnostic system 512, but includes a gas purgepassageway 556. The diagnostic system 612 includes a passageway 646,which is substantially similar in operation as the passageway 56 in FIG.2 and the passageway 556 in FIG. 9. The passageway 646 has a length Ldefined in this embodiment as the distance from the chamber opening 22to the gas purge passageway 556. As discussed above, the length L of thepassageway 646 can be selected to be longer than the gas mean free pathof contaminant molecules at the selected process conditions.

The gas purge passageway 556 operates in substantially the same manneras the gas purge passageway 56 described above with respect to FIG. 2.The above description of other elements of the diagnostic system 512 (asshown in FIG. 9) will not be repeated with respect to FIG. 10 forsimplicity.

The diameter D of the passageway 646 can be equal to, smaller or largerthan the diameter of the opening 22 formed in the chamber wall 36.

The length L and the diameter D of the passageway 646 are selected toprovide a length to diameter ratio (L/D) of at least 4, which can beobtained by dividing the length L of the passageway by the diameter D ofthe passageway 646. The passageway 646 can be configured to providelength to diameter ratios greater than 4 depending on the plasma processbeing used process characteristics, e.g., processing chamber pressure,chamber gas flow and chamber gas temperature, thereof. The gas purgepassageway 646 helps further reduce contamination of the diagnosticsensing element 539 (and in turn the diagnostic sensor).

FIG. 11 shows a diagnostic system 712 that is an alternative embodimentof the diagnostic system 512, which operates in a substantially similarmanner as the diagnostic system 512. The diagnostic system 712 has asubstantially similar construction as the diagnostic system 512 shown inFIG. 9, but includes a flow restrictor element 550 positioned along theinterior surface 545 of the mounting wall 544.

The flow restrictor element 550, which may be made from the samematerials as the flow restrictor element 50 described above, extendsalong the interior surface 545 of the mounting wall 544 from the chamberopening 22 to the diagnostic sensor element 539 or to the diagnosticsensor. The flow restrictor element 550 has an interior surface 555 thatdefines a passageway 746 having a predetermined diameter D. The diameterD of the passageway 746 can be equal to, smaller or larger than thediameter of the opening 22 formed in the chamber wall 36. Asillustrated, the diameter D of the passageway 746 is smaller than theopening 22.

The passageway 746 has a predetermined length L, which can be defined inthis embodiment as the distance from the chamber opening 22 to thediagnostic sensor element 539 or to the diagnostic sensor. As discussedabove, the length L of the passageway 746 can be selected to be longerthan the gas mean free path of contaminant molecules at the selectedprocess conditions.

The length L and the diameter D of the passageway 746 are selected toprovide a length to diameter ratio (L/D) of at least 4, which can beobtained by dividing the length L of the passageway by the diameter D ofthe passageway 746. The passageway 746 can be configured to providelength to diameter ratios greater than 4 depending on the plasma processbeing used or process characteristics, e.g., processing chamberpressure, chamber gas flow and chamber gas temperature, thereof.

FIG. 12 shows a diagnostic system 812, which is an alternativeembodiment of the diagnostic system 712. The diagnostic system 812operates in a substantially similar manner as the diagnostic system 712shown in FIG. 9, but includes a flow restrictor element 650 having anend portion 639 configured to abut a recessed portion 637 of a chamberwall 636.

The diagnostic system 812 provides another way to implement a flowrestrictor element into a diagnostic system. Specifically, in thediagnostic system 812, an end portion 639 of the flow restrictor element650 is configured to abut a recessed portion 637 formed in the chamberwall 636.

The flow restrictor element 650, which may be made from the samematerials as the flow restrictor element 50 described above, extendsfrom the recessed portion 637, which is adjacent to the chamber opening22, to the diagnostic sensor element 539 or to the diagnostic sensor.The flow restrictor element 650 defines a passageway 846 having apredetermined diameter D. The diameter D of the passageway 846 can beequal to, smaller or larger than the diameter of the opening 22 formedin the chamber wall 36. As illustrated, the diameter D of the passageway846 is smaller than the opening 22.

The passageway 846 has a predetermined length L, which can be defined inthis embodiment as the distance from the end portion 637 of the flowrestrictor element 650 to the diagnostic sensor element 539 or to thediagnostic sensor. As discussed above, the length L of the passageway846 can be selected to be longer than the gas mean free path ofcontaminant molecules at the selected process conditions.

The length L and the diameter D of the passageway 846 are selected toprovide a length to diameter ratio (L/D) of at least 4, which can beobtained by dividing the length L of the passageway by the diameter D ofthe passageway 846. The passageway 846 can be configured to providelength to diameter ratios greater than 4 depending on the plasma processbeing used or process characteristics, e.g., processing chamberpressure, chamber gas flow and chamber gas temperature, thereof.

FIG. 13 shows a diagnostic system 912 is an alternative embodiment ofthe diagnostic system 512, which operates in a substantially similarmanner as the diagnostic system 512. The diagnostic system 912 has asubstantially similar construction as the diagnostic system 512 shown inFIG. 9, but includes a tapered flow restrictor element 750 positionedalong a tapered interior surface 745 of a mounting wall 744.

The diagnostic system 912 includes a mounting portion 738, which can bemade from the same materials as the mounting portion 38 described above.The mounting portion 738 has the tapered mounting wall 744 coupled tothe chamber wall 36 by one or more fasteners 537. The fastener(s) may beone or more of a seal, an O-ring or any other type of sealing fastenercapable of coupling the mounting wall 744 to the chamber wall 36.

The flow restrictor element 750, which may be made from the samematerials as the flow restrictor element 50 described above, extendsalong the interior surface 745 of the mounting wall 744 from the chamberopening 22 to the diagnostic sensor element 539 or to the diagnosticsensor. The flow restrictor element 750 has a tapered outer surface 755,which abuts the opening in the chamber wall 36 to help support the flowrestrictor element 750 within the chamber wall 36. The flow restrictorelement 750 defines a passageway 946 having a predetermined diameter D.The diameter D of the passageway 946 can be equal to, smaller or largerthan the diameter of the opening 22 formed in the chamber wall 36.

As illustrated, the diameter D of the passageway 946 is smaller than theopening 22 and is constant along the length L thereof. However, thepassageway 946 can have a variable diameter configured to increase ordecrease along the passageway 946. For example, the diameter D of thepassageway 946 can incrementally increase in a direction toward thediagnostic sensor element 539 or to the diagnostic sensor, as shown inFIG. 13. Alternatively, the diameter D of the passageway 946 canincrementally decrease in a direction toward the diagnostic sensorelement 539 or to the diagnostic sensor.

The passageway 946 has a predetermined length L, which can be defined inthis embodiment as the distance from the chamber opening 22 to thediagnostic sensor element 539 or to the diagnostic sensor. As discussedabove, the length L of the passageway 946 can be selected to be longerthan the gas mean free path of contaminant molecules at the selectedprocess conditions.

The length L and the diameter D of the passageway 946 are selected toprovide a length to diameter ratio (L/D) of at least 4, which can beobtained by dividing the length L of the passageway by the diameter D ofthe passageway 946. The passageway 946 can be configured to providelength to diameter ratios greater than 4 depending on the plasma processbeing used or process characteristics, e.g., processing chamberpressure, chamber gas flow and chamber gas temperature, thereof. Inpassageways having a variable diameter D, an average diameter along alength L thereof can be used to provide the length to diameter ratio(L/D) of at least 4.

FIG. 14 shows a diagnostic system 1012, which has substantially the sameconstruction as the diagnostic system 712, but includes the gas purgepassageway 556. The diagnostic system 1012 also includes the passageway746, which has a length L defined as the distance from the chamberopening 22 to the gas purge passageway 556. As discussed above, thelength L of the passageway 746 can be selected to be longer than the gasmean free path of contaminant molecules at the selected processconditions.

FIG. 15 shows a diagnostic system 1112, which has substantially the sameconstruction as the diagnostic system 812, but includes the gas purgepassageway 556. The diagnostic system 1112 also includes the passageway846, which has a length L defined as the distance from the end portion637 of the flow restrictor element 650 to the gas purge passageway 556.As discussed above, the length L of the passageway 846 can be selectedto be longer than the gas mean free path of contaminant molecules at theselected process conditions.

FIG. 16 shows a diagnostic system 1212, which has substantially the sameconstruction as the diagnostic system 912, but includes the gas purgepassageway 556. The diagnostic system 1212 also includes the passageway946, which has a length L defined as the distance from the chamberopening 22 to the gas purge passageway 556. As discussed above, thelength L of the passageway 946 can be selected to be longer than the gasmean free path of contaminant molecules at the selected processconditions.

Although a passageway having a variable diameter D is only described inrelation to the passageway 946, other passageways, e.g., passageways 46,546, 646, 746 and 846, described herein can also be configured to have avariable diameter, e.g., increasing or decreasing along a length of thepassageway.

FIG. 17 shows a method in accordance with principles of the invention.The method is for operating a diagnostic system in conjunction with aplasma processing system. The plasma processing system has a chambercontaining a plasma processing region in which a plasma can be generatedduring a plasma process and the diagnostic system is positioned in anoptical diagnostic chamber coupled to the plasma processing region.

The method starts at 1300. At 1302, contamination of a diagnostic sensoris substantially reduced. The backflow of contaminants from the plasmaprocessing chamber through the passageway (and a pre-chamber area, ifprovided) to the diagnostic sensor associated with the plasma processingsystem can be substantially reduced. For example, the plasma issubstantially shielded from entering the passageway (and a pre-chamberarea, if provided) formed in the diagnostic system between thediagnostic system and the plasma processing chamber or vicinitiesthereof. A purge gas can be introduced into the pre-chamber area forsubstantially shielding the plasma from entering the passageway and thepre-chamber area. The method can comprise acts, operations orprocedures, such as, for example, providing a heating element, a coolingelement, an electric field, or a magnetic field, in combination orseparately, to reduce contamination of the pre-chamber and passagewayconnecting the pre-chamber and the plasma processing chamber. Variouscombinations of these additional acts, operations or procedures could beused as well. For example, a diagnostic system could employ a magneticfield and an electric field, in combination with or separate from, thepurge gas to shield plasma from entering the pre-chamber and thepassageway.

At 1304, a condition of the plasma process is detected by a diagnosticsystem capable of receiving the condition, e.g., light, gas or pressure,from the plasma processing region and/or the substrate. For example, aplasma processing condition, such as an endpoint of the plasma process,can be detected using the diagnostic system. At 1306, the method ends.

One such method to detect a plasma process condition through an opticalwindow is disclosed in U.S. Application of Mitrovic et al., AttorneyDocket 291738, filed concurrently herewith, the contents of which areincorporated by reference herein in their entirety.

While the present invention has been particularly shown and describedwith reference to the preferred embodiments thereof, it will beunderstood by those skilled in the art that various changes in form anddetails can be made therein without departing from the spirit and scopeof the invention.

For example, the system 12 can be used with substantially all diagnosticsystems with only slight modifications for the introduction of laserbeams for diagnostic purposes or materials processing, into a processingchamber. The system 12 can be associated with one or more RF probes orantennas configured to monitor harmonic content of the plasma. Forexample, one or more RF probes can be mounted outside the plasmaprocessing chamber 14, e.g., to replace or in conjunction with thediagnostic sensor 40, to monitor RF energy from the plasma processingchamber 14 and analyze harmonic content thereof.

Thus, the foregoing embodiments have been shown and described for thepurpose of illustrating the functional and structural principles of thisinvention and are subject to change without departure from suchprinciples. Therefore, this invention includes all modificationsencompassed within the spirit and scope of the following claims.

1. A plasma processing system comprising: a processing chamber having anopening formed in a wall thereof and containing a plasma processingregion; a chuck, constructed and arranged to support a substrate withinthe chamber in the processing region; a plasma generator incommunication with the chamber, the plasma generator being constructedand arranged to generate a plasma during a plasma process in the plasmaprocessing region; and a diagnostic system having a diagnostic sensor incommunication with the chamber and being constructed and arranged tosubstantially reduce contamination of the diagnostic sensor, thediagnostic system including a passageway formed between the plasmaprocessing region and the diagnostic sensor and having a predeterminedlength and a predetermined diameter, wherein the passageway has a lengthto diameter ratio, provided by dividing the predetermined length by thepredetermined diameter, of at least
 4. 2. The plasma processing systemof claim 1, wherein the diagnostic system is constructed and arranged todetect a plasma process and/or substrate condition associated with thechamber.
 3. The plasma processing system of claim 1, wherein thediagnostic system includes a restrictor element positioned in thepassageway.
 4. The plasma processing system of claim 3, wherein therestrictor element is positioned adjacent the opening in the chamber. 5.The plasma processing system of claim 3, wherein the restrictor elementis configured to abut a recessed portion of the chamber.
 6. The plasmaprocessing system of claim 3, wherein the restrictor element has atapered outer surface.
 7. The plasma processing system of claim 1,wherein the diagnostic system includes a purge gas port in communicationwith the passageway, the purge gas port being capable of supplying apurge gas to purge the passageway.
 8. The plasma processing system ofclaim 7, wherein the restrictor element is configured to create a higherpressure of purge gas passed through the passageway due to reduced flowconductance.
 9. The plasma processing system of claim 1, wherein thediagnostic sensor is constructed and arranged to detect a plasma processand/or a substrate condition associated with the plasma processingregion.
 10. The plasma processing system of claim 9, wherein thediagnostic sensor includes an optical assembly.
 11. The plasmaprocessing system of claim 9, wherein the plasma process condition is anendpoint of the plasma process.
 12. The plasma processing system ofclaim 1, further comprising an electric field generator configured toproduce an electric field at least in the passageway or a vicinitythereof adjacent to the plasma processing chamber.
 13. The plasmaprocessing system of claim 12, wherein the electric field generatorcomprises an electrode assembly having at least one electrode.
 14. Theplasma processing system of claim 12, further comprising an insulatorsubstantially surrounding the electric field generator.
 15. The plasmaprocessing system of claim 14, further comprising a power supply coupledto the electric field generator to supply power to the electric fieldgenerator.
 16. The plasma processing system of claim 15, wherein thepower is DC or RF biased power.
 17. The plasma processing system ofclaim 1, further comprising a magnetic field generator configured toproduce a magnetic field at least in the passageway or a vicinitythereof adjacent to the plasma processing chamber.
 18. The plasmaprocessing system of claim 17, further comprising a magnetic fieldleakage reducing member substantially surrounding the magnetic fieldgenerator.
 19. The plasma processing system of claim 17, wherein themagnetic field generator comprises a plurality of magnets.
 20. Theplasma processing system of claim 19, wherein the plurality of magnetsis positioned around the passageway such that each magnet of theplurality of magnets has a polarization direction separated from apolarization direction of an adjacent magnet by twice the separationangle between the magnets.
 21. The plasma processing system of claim 19wherein the plurality of magnets is positioned around the passagewaysuch that each magnet of the plurality of magnets has a polarizationdirection directed in the same radial direction.
 22. The plasmaprocessing system of claim 19 wherein the plurality of magnets ispositioned around the passageway such that alternate magnets of theplurality of magnets have a polarization direction directed in oppositeradial directions.
 23. The plasma processing system of claim 17, whereinthe magnetic field generator comprises at least one current-carryingcoil.
 24. The plasma processing system of claim 1, wherein the wall ofthe chamber has a thickness that is less than the predetermined lengthof the passageway.
 25. The plasma processing system of claim 1, furthercomprising a fluid chamber surrounding the passageway.
 26. The plasmaprocessing system of claim 25, further comprising a fluid inlet incommunication with the fluid chamber and a fluid outlet in communicationwith the fluid chamber, wherein a fluid having a certain temperature canbe supplied to the fluid chamber through the fluid inlet and can beremoved from the fluid chamber through the fluid outlet.
 27. The plasmaprocessing system of claim 25, further comprising a temperaturecontrolled system associated with the fluid chamber and being capable ofcontrolling a temperature of a fluid within the fluid chamber.
 28. Theplasma processing system of claim 27, wherein the temperature controlledsystem is configured to heat the fluid within the fluid chamber.
 29. Theplasma processing system of claim 27, wherein the temperature controlledsystem is configured to cool the fluid within the fluid chamber.
 30. Theplasma processing system of claim 1, wherein the passageway has avariable diameter such that the predetermined diameter increases ordecreases along the length of the passageway.
 31. A method for operatinga diagnostic system in conjunction with a plasma processing systemhaving a processing chamber containing a plasma processing region inwhich a plasma can be generated during a plasma process, the diagnosticsystem including a diagnostic sensor and being coupled to the plasmaprocessing region, the method comprising: providing a passageway formedbetween the plasma processing chamber and the diagnostic sensor, thepassageway having a length to diameter ratio, provided by dividing apredetermined length of the passageway by a predetermined diameter ofthe passageway, of at least 4; substantially reducing contamination ofthe diagnostic sensor; and detecting a condition of the plasma processand/or a substrate in the processing chamber with the diagnostic sensor.32. The method of claim 31, further comprising restricting thepassageway to a predetermined length and a predetermined diameter with arestrictor element.
 33. The method of claim 31, further comprisingtapering the passageway so that the predetermined diameter increases ordecreases along the passageway.
 34. The method of claim 31, wherein thesubstantially reducing includes providing fluid of a certain temperaturesubstantially surrounding the passageway.
 35. The method of claim 34,wherein the substantially reducing includes heating fluid substantiallysurrounding the passageway to a certain temperature.
 36. The method ofclaim 34, wherein the substantially reducing includes cooling fluidsubstantially surrounding the passageway to a certain temperature. 37.The method of claim 31, wherein the substantially reducing includesproducing an electric field at least in the passageway or a vicinitythereof adjacent to the plasma processing chamber.
 38. The method ofclaim 31, wherein the substantially reducing includes producing amagnetic field at least in the passageway or a vicinity thereof adjacentto the plasma processing chamber.
 39. The method of claim 31, whereinthe substantially reducing includes: producing an electric field atleast in the passageway or a vicinity thereof adjacent to the plasmaprocessing chamber; and producing a magnetic field at least in thepassageway or a vicinity thereof adjacent to the plasma processingchamber.
 40. The method of claim 31, wherein the substantially reducingincludes: providing fluid of a certain temperature substantially aroundthe passageway; and producing a magnetic field at least in thepassageway or a vicinity thereof adjacent to the plasma processingchamber.
 41. The method of claim 40, wherein the providing fluid of acertain temperature includes heating fluid substantially surrounding thepassageway to the certain temperature.
 42. The method of claim 40,wherein the providing fluid of a certain temperature includes coolingfluid substantially surrounding the passageway to the certaintemperature.
 43. The method of claim 31, wherein the substantiallyreducing includes: providing fluid of a certain temperaturesubstantially around the passageway; and producing an electric field atleast in the passageway or a vicinity thereof adjacent to the plasmaprocessing chamber.
 44. The method of claim 43, wherein the providingfluid of a certain temperature includes heating fluid substantiallysurrounding the passageway to the certain temperature.
 45. The method ofclaim 43, wherein the providing fluid of a certain temperature includescooling fluid substantially surrounding the passageway to the certaintemperature.
 46. The method of claim 31, wherein the substantiallyreducing includes: providing fluid of a certain temperaturesubstantially around the passageway; producing an electric field atleast in the passageway or a vicinity thereof adjacent to the plasmaprocessing chamber; and producing a magnetic field at least in thepassageway or a vicinity thereof adjacent to the plasma processingchamber.
 47. The method of claim 46, wherein the providing fluid of acertain temperature includes heating fluid substantially surrounding thepassageway to the certain temperature.
 48. The method of claim 46,wherein the providing fluid of a certain temperature includes coolingfluid substantially surrounding the passageway to the certaintemperature.
 49. A plasma processing system comprising: a chamber havingan opening of a selected diameter and containing a plasma processingregion; a chuck, constructed and arranged to support a substrate withinthe chamber in the processing region; a plasma generator incommunication with the chamber, the plasma generator being constructedand arranged to generate a plasma during a plasma process in the plasmaprocessing region; a diagnostic system having a diagnostic sensor incommunication with the chamber; a passageway formed between the plasmaprocessing region and the diagnostic sensor; and an electric fieldgenerator configured to produce an electric field at least in thepassageway or a vicinity thereof adjacent to the plasma processingchamber such that contamination of the diagnostic sensor is reduced. 50.The plasma processing system of claim 49, wherein the electric fieldgenerator comprises an electrode assembly having at least one electrode.51. The plasma processing system of claim 50, further comprising aninsulator substantially surrounding the electric field generator. 52.The plasma processing system of claim 51, further comprising a powersupply coupled to the electric field generator to supply power to theelectric field generator.
 53. The plasma processing system of claim 52,wherein the power is DC or RF biased power.
 54. A plasma processingsystem comprising: a chamber having an opening of a selected diameterand containing a plasma processing region; a chuck, constructed andarranged to support a substrate within the chamber in the processingregion; a plasma generator in communication with the chamber, the plasmagenerator being constructed and arranged to generate a plasma during aplasma process in the plasma processing region; a diagnostic systemhaving a diagnostic sensor in communication with the chamber; apassageway formed between the plasma processing region and thediagnostic sensor; and a magnetic field generator configured to producea magnetic field at least in the passageway or a vicinity thereofadjacent to the plasma processing chamber such that contamination of thediagnostic sensor is reduced.
 55. The plasma processing system of claim54, further comprising a magnetic field leakage reducing membersubstantially surrounding the magnetic field generator.
 56. The plasmaprocessing system of claim 54, wherein the magnetic field generatorcomprises a plurality of magnets.
 57. The plasma processing system ofclaim 56, wherein the plurality of magnets is positioned around thepassageway such that each magnet of the plurality of magnets has apolarization direction separated from a polarization direction of anadjacent magnet by twice the separation angle between the magnets. 58.The plasma processing system of claim 56, wherein the plurality ofmagnets is positioned around the passageway such that each magnet of theplurality of magnets has a polarization direction directed in the sameradial direction.
 59. The plasma processing system of claim 56, whereinthe plurality of magnets is positioned around the passageway such thatalternate magnets of the plurality of magnets have a polarizationdirection directed in opposite radial directions.
 60. The plasmaprocessing system of claim 55, wherein the magnetic field generatorcomprises at least one current-carrying coil.
 61. A plasma processingsystem comprising: a chamber having an opening of a selected diameterand containing a plasma processing region; a chuck, constructed andarranged to support a substrate within the chamber in the processingregion; a plasma generator in communication with the chamber, the plasmagenerator being constructed and arranged to generate a plasma during aplasma process in the plasma processing region; a diagnostic systemhaving a diagnostic sensor in communication with the chamber; apassageway formed between the plasma processing region and thediagnostic sensor; and a temperature controlled system including a fluidchamber surrounding the passageway, the temperature controlled systembeing capable of controlling a temperature of a fluid within the fluidchamber.
 62. The plasma processing system of claim 61, wherein thetemperature controlled system includes a fluid inlet in communicationwith the fluid chamber and a fluid outlet in communication with thefluid chamber, wherein the fluid having a certain temperature can besupplied to the fluid chamber through the fluid inlet and can be removedfrom the fluid chamber through the fluid outlet.
 63. The plasmaprocessing system of claim 61, wherein the temperature controlled systemis configured to heat the fluid within the fluid chamber to the certaintemperature.
 64. The plasma processing system of claim 61, wherein thetemperature controlled system is configured to cool the fluid within thefluid chamber to the certain temperature.
 65. A method for operating adiagnostic system in conjunction with a plasma processing system havinga processing chamber containing a plasma processing region in which aplasma can be generated during a plasma process, the diagnostic systemincluding a diagnostic sensor and being coupled to the plasma processingregion, the method comprising: producing an electric field at least in apassageway formed between the plasma processing chamber and thediagnostic sensor or a vicinity thereof adjacent to the plasmaprocessing chamber to substantially reduce contamination of thediagnostic sensor; and detecting a condition of the plasma processand/or a substrate in the processing chamber with the diagnostic sensor.66. A method for operating a diagnostic system in conjunction with aplasma processing system having a processing chamber containing a plasmaprocessing region in which a plasma can be generated during a plasmaprocess, the diagnostic system including a diagnostic sensor and beingcoupled to the plasma processing region, the method comprising:producing a magnetic field at least in a passageway formed between theplasma processing chamber and the diagnostic sensor or a vicinitythereof adjacent to the plasma processing chamber to substantiallyreduce contamination of the diagnostic sensor; and detecting a conditionof the plasma process and/or a substrate in the processing chamber withthe diagnostic sensor.
 67. A method for operating a diagnostic system inconjunction with a plasma processing system having a processing chambercontaining a plasma processing region in which a plasma can be generatedduring a plasma process, the diagnostic system including a diagnosticsensor and being coupled to the plasma processing region, the methodcomprising: controlling a temperature of a fluid within a fluid chambersurrounding a passageway formed between the plasma processing chamberand the diagnostic sensor to substantially reduce contamination of thediagnostic sensor; and detecting a condition of the plasma processand/or a substrate in the processing chamber with the diagnostic sensor.68. The plasma processing system of claim 3, wherein at least one of therestrictor element and a mounting portion substantially surrounding thepassageway are made from a metal, a dielectric material and asemiconductor material.
 69. The plasma processing system of claim 49,wherein the diagnostic system includes a restrictor element positionedin the passageway.
 70. The plasma processing system of claim 69, whereinat least one of the restrictor element and a mounting portionsubstantially surrounding the passageway are made from a metal, adielectric material and a semiconductor material.
 71. The plasmaprocessing system of claim 54, wherein the diagnostic system includes arestrictor element positioned in the passageway.
 72. The plasmaprocessing system of claim 71, wherein at least one of the restrictorelement and a mounting portion substantially surrounding the passagewayare made from a metal, a dielectric material and a semiconductormaterial.
 73. The plasma processing system of claim 61, wherein thediagnostic system includes a restrictor element positioned in thepassageway.
 74. The plasma processing system of claim 63, wherein atleast one of the restrictor element and a mounting portion substantiallysurrounding the passageway are made from a metal, a dielectric materialand a semiconductor material.